嵌入式网络视频服务器的设计

网络视频服务器集视频采集、实时压缩、网络传输等功能于一体,应用领域广泛。介绍了一种嵌入式网络视频服务器的实现方案,采用MPC860T作为主CPU,实现对音视频编解码芯片AT2042及视频采集芯片TVP5150的控制,并实现了数字视频信号的网络传输功能。给出了网络视频服务器的软、硬件实现方法。     

基于VxWorks的嵌入式网络视频服务器设计

网络视频服务器是一种嵌入式数字远程监控系统,它集视频采集、实时压缩和网络传输等功能为一体,本文提出了基于VxWorks平台的网络视频服务器的实现方案,在介绍实时操作系统VxWorks和MPC860T的基础上,结合音视频编解码芯片AT2042,给出了网络视频服务器的软、硬件实现方法。     

网络流媒体服务器的机制与实现研究

网络流媒体服务器是指在IP网络上提供实时视频(音频)流服务的网络服务器，对服务器的机制与实现进行了深入研究，在RTP／RTCP协议和RTSP协议基础上，提出了“生产者线程-消费者线程”的架构，用面向对象的方法和事件驱动的机制实现服务器异步工作方式，充分利用系统资源，提高了服务器的并发性和实时性。基于反馈报文的流服务器流量自调节，解决了网络拥塞时实时数据传输的问题。     

谈网络视频服务器的应用及网络视频的存储

近年来随着网络视频技术的成熟，网络视频服务器（Network Video Server）和网络摄像机（IP Camera）得到了迅速的发展并在各行业普及应用。那么网络视频服务器这类产品依网而生，它对网络环境条件又有什么要求宁它在我们的生活中可以扮演什么样的角色宁它的视频资料又是怎样存储呢宁在此仅以此文聊作抛砖引玉，希望有更多的朋友关注网络视频服务器类产品的发展。由于网络摄像机的原理和视频服务器类似，我们也把它当成网络视频服务器来讨论。[编者按]     

基于MSP430的休眠唤醒装置设计

针对矿用救灾指挥装置网络视频服务器采用电池供电工作时间短的缺点,采用MSP430低功耗单片机设计了一种休眠唤醒装置,实现了网络视频服务器的休眠唤醒功能,延长了网络视频服务器电池的使用时间,使得多次救援、持续作业成为可能。     

网络视频服务器产品精选

USP-FWQ-02网络视频服务器，CYNVS-WD4四路网络视频服务器，HB18系列DVR专用视频压缩卡，LC8001MF单路视频服务器，CSV1504TA四路网络视频服务器……     

基于AT2042的网络视频服务器的设计与实现

详细介绍了Pentalnicro公司的2通道A/V编解码器AT2042的功能结构、主要特点和通信接口的基础上，提出了一种基于AT2042的网络视频服务器的设计与实现方案，给出了基于AT2042的网络视频服务器的硬件实现方案和软件系统体系结构，系统的软、硬件均采用模块化结构，配置和管理灵活方便，最大限度的考虑了网络带宽的利用率，具有广阔的市场和应用前景。     

多路嵌入式H．264视频服务器的设计

介绍了一种基于Linux操作系统的多路嵌入式H．264视频服务器的设计方案。该方案给出了系统的硬件组成和软件设计框架．然后说明了发送端和接收端的实现过程，并对网络传输中利用RTP实现QoS机制做了说明。实验结果表明，上述设计的多路嵌入式视频服务器在不影响图象质量的前提下，能够比以往的视频服务器占用更低的带宽。     

基于AVS的编码视频服务器方案

本文介绍了AVS的主要技术和优点,根据网络视频服务器的需求,阐述了基于AVS标准的视频服务器的实现方案。     

视频服务器选择和应用探讨

由于视频服务器是依托于网络来实现视频传输的监控产品，因而它受网络环境的影响很大，同时产品本身的性能亦是不可忽视的重要环节。从众多厂家、工程商及用户的使用情况反映来看，目前视频服务器的使用主要存在着产品不够稳定、带宽不足、网络延迟过长、丢包、清晰度不够、兼容集成困难等问题。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate